Effect of Sintering Temperature on Electrical Properties of WO3-Based Capacitor-Varistor Ceramics

The effect of sintering temperature on the microstructure, nonlinear electrical behavior, and dielectric properties of the Y2O3-doped WO3 ceramics was studied. The decrease in breakdown voltage directly relates to the grain growth of WO3 grains when increasing the sintering temperatures from 1050 to 1200 degrees C. The capacitor-varistor of WO3- 0.8 mol% Y2O3 composite sintered at 1150 degrees C exhibits the maximal nonlinear coefficient of 3.5 and the highest dielectric constant of 1.13 x 10(4). However, higher sintering temperature than 1150 degrees C is not favorable for the nonlinear electrical behavior of the WO3 ceramics. The best nonlinear properties of the samples sintered at 1150 degrees C can be explained by the most efficient boundary barrier layer with can be formed sintered at the proper temperature.